Complete reference index
Read each signal’s meaning, context and limitations. Use the interactive cards above for visual or listening practice.
A — Alfa
I have a diver down; keep well clear at slow speed.
Displayed when a vessel has a diver down. Other vessels should keep well clear and proceed at slow speed; local rules may add requirements.
Source: International Code of Signals
B — Bravo
I am taking in, discharging, or carrying dangerous goods.
The red Bravo flag is used in the dangerous-goods contexts defined by applicable rules.
Source: International Code of Signals
C — Charlie
Yes / affirmative.
The single-letter International Code signal is affirmative.
Source: International Code of Signals
D — Delta
Keep clear of me; I am manoeuvring with difficulty.
Three horizontal bands—yellow, blue, yellow. Read it with the vessel’s lights, shapes and situation.
Source: International Code of Signals
E — Echo
I am altering my course to starboard.
Two horizontal bands: blue above red.
Source: International Code of Signals
F — Foxtrot
I am disabled; communicate with me.
A red diamond on a white field. Use the full situation and other signals to understand what assistance or communication is needed.
Source: International Code of Signals
G — Golf
I require a pilot. When made by a fishing vessel near fishing grounds, it can mean “I am hauling nets.”
Six alternating vertical yellow and blue stripes. Context distinguishes the pilot request from the fishing-related meaning.
Source: International Code of Signals
H — Hotel
I have a pilot on board.
Two vertical halves: white at the hoist and red at the fly.
Source: International Code of Signals
I — India
I am altering my course to port.
A yellow flag with a small black disc in the centre.
Source: International Code of Signals
J — Juliett
I am on fire and have dangerous cargo on board; keep well clear of me.
Three horizontal bands—blue, white, blue. This is a serious warning signal.
Source: International Code of Signals
K — Kilo
I wish to communicate with you.
A single-letter request to communicate; a response can be made using the applicable signalling method.
Source: International Code of Signals
L — Lima
You should stop your vessel instantly.
Four quarters: yellow at upper-left and lower-right; black at upper-right and lower-left.
Source: International Code of Signals
M — Mike
My vessel is stopped and making no way through the water.
A white diagonal cross (saltire) on a blue field.
Source: International Code of Signals
N — November
No / negative.
A four-by-four blue-and-white checkerboard. In the International Code, it does not by itself request passage under a bridge.
Source: International Code of Signals
O — Oscar
Man overboard.
Two diagonal fields: yellow at the lower hoist and red at the upper fly.
Source: International Code of Signals
P — Papa
In harbour: all personnel report aboard, as the vessel is about to proceed to sea. At sea for a fishing vessel: my nets have come fast upon an obstruction.
The Blue Peter has a harbour departure meaning; its fishing-related meaning at sea is different.
Source: International Code of Signals
Q — Quebec
My vessel is healthy and I request free pratique.
A plain yellow flag. “Quarantine flag” is a common nickname, but the single-letter Code meaning is a health/pratique request—not that the vessel is quarantined.
Source: International Code of Signals
R — Romeo
No single-letter meaning is assigned in the current International Code of Signals.
Romeo is still an alphabet flag and may appear as part of a spelled message or a multi-flag code. Do not invent a standalone meaning.
Source: International Code of Signals
S — Sierra
My engines are going astern.
A white field with a blue square in the centre.
Source: International Code of Signals
T — Tango
Keep clear of me; I am engaged in pair trawling.
Three vertical bands—red, white, blue—with a fishing-related meaning.
Source: International Code of Signals
U — Uniform
You are standing into danger.
Four quarters: red at upper-left and lower-right; white at upper-right and lower-left.
Source: International Code of Signals
V — Victor
I require assistance.
A red diagonal cross (saltire) on a white field. This is an assistance signal, not a substitute for the correct distress alert.
Source: International Code of Signals
W — Whiskey
I require medical assistance.
A white square with a smaller red square in its centre, on a blue field.
Source: International Code of Signals
X — X-ray
Stop carrying out your intentions and watch for my signals.
A white field with an upright blue cross (not a diagonal X).
Source: International Code of Signals
Y — Yankee
I am dragging my anchor.
A yellow flag crossed by diagonal red stripes.
Source: International Code of Signals
Z — Zulu
I require a tug. When made by a fishing vessel, it can mean “I am shooting nets.”
A four-colour diagonal flag. Its meaning depends on the vessel and context.
Source: International Code of Signals